Canagliflozin (compound of formula I), chemically named as 1-(β-D-glucopyranosyl)-4-methyl-3-[5-(4-fluorophenyl)-2-thienylmethyl]benzene, is developed by Janssen Pharmaceutical Ltd., a subsidiary of Johnson & Johnson Pharmaceutical Ltd. It was approved by FDA as a hypoglycemic drug for treating type II diabetes on Mar. 29, 2013, and is the first FDA-approved sodium-glucose cotransporter 2 (SGLT2) inhibitor. SGLT2 inhibitors can specifically inhibit glucose uptake of kidney, which allows excess glucose to be excreted in the urine and thus directly reduces blood sugar levels.

Up to present, the reported crystalline form of canagliflozin includes a hemihydrate crystalline form of canagliflozin as disclosed in WO2008069327. However, this crystalline form has shortcomings such as small crystalline particles as well as large static electricity, so that there are negative effects on preparation of pharmaceutical formulations.
US2009/0233874A1 disclosed another crystalline form of canagliflozin and a preparation method thereof. However, the appearance of crystal obtained by this method was gray white, while canagliflozin crystals with high purity should be pure white.
CN103554092A disclosed a crystalline form named as form B, and CN103588762A disclosed two crystalline forms named as form C and form D. Form B and form C were acquired by volatilizing organic solvent from a mixed solvent containing 50% of water at room temperature and form D was obtained by heating form C so as to remove the solvent. However, industrial production of above three crystalline forms is difficult to achieve.
CN103980261A, CN103980262A and CN103936725A disclosed another three crystalline forms of canagliflozin named as form A, form B and form C, wherein form A was a crystal with long flake shape and poor liquidity, form B had a poor reproducibility of preparation, and form C had low crystallinity and contained some amorphous form.
CN104130246A disclosed a crystalline form named as form E which also had low crystallinity as well as incomplete crystal transformation and contained some amorphous form.
WO2014/180872A1 disclosed a non-stoichiometric hydrate crystalline form of canagliflozin. Since the water content of this form was non-stoichiometric, the crystalline characteristics also could not be fully determined. It was difficult to ensure preparation of crystalline form with a consistent quality in a large-scale production process.
CN103936726A disclosed form III and form IV of canagliflozin, wherein form III was an octanol solvate while form IV was an anhydrous form. Since octanol is of high boiling point, it is difficult for the residual octanol in form III to meet requirements of pharmacopoeia. Form IV was obtained by pulping form III in n-heptane and then drying in vacuo for 24 hours. The time for in vacuo drying was long because it was required to fully removal of solvent octanol. When products are dried in large quantities in industry, the residual octanol may easily exceed the required limits.
In summary, there is an urgent need in the art to develop a new crystalline form of canagliflozin with high purity, stable physical and chemical properties, excellent reproducibility and industrial production suitability.